Therapeutic Indications:
TERRAMYCIN with Polymyxin B Ophthalmic Ointment is indicated
in the treatment of superficial ocular infections involving the
conjunctive and/or cornea due to susceptible microorganisms.Posology and Method of Administration :TERRAMYCIN with Polymyxin B Ophthalmic is administered as a small quantity (approximately 1 cm) of the ointment. The preparation should be applied into the conjunctival sac of the lower lid 4 to 6 times daily until the infection is cleared anq; healing is complete. This may take from one day to several weeks depending on the nature and severity of the infection. In blepharitis, scales and crusts should be removed before applying medication, For prophylaxis, the same procedure is followed on the day before the operation and subsequently for several days following it. The patient should be instructed to avoid contamination of the tip of the tube when applying the ointment.

Contraindications :

This product is contraindicated in persons who have shown
hyperesnsitivity to any of Its components.

Special Warnings and Special Precautions for Use :

As with other antibiotic preparations, TERRAMYCIN may result
in overgrow1h of nonsusceptible organisms, including fungi,
constant observation of the patient for this possibility is essential.
If new infections due to non susceptible bacteria or fungi appear
during therapy, appropriate measures should be taken.
TERRAMYCIN with Polymyxin B should be supplemented with
systemic administration when infections are severe or do not
respond to topical therapy alone.Usage in Children
Systemic administration of tetracyclines during tooth development
(last half of pregnancy, infancy, and childhood to the age of
8 years) may cause permanent discoloration of the teeth as
well as retardation in the development of the skeleton. Enamel
hypoplasia has also been reported. Although these effects are
unlikely doses used, the possibility that these effects could occur
should be considered.

Interaction with other Medicaments and other Forms of interaction :

None established

Pregnancy and Lactation :

Pregnancy
There are no controlled studies to date using topical tetracyclines in pregnant women. The use of systemic tetracyciines in pregnant women has resulted in retardation of skeletal development and bone growth in the letus. None the less, topical tetracyclines should be used during pregnancy only when the possible benefits outweight the potential risks.Lactation
It is not known whether topically applied tetracyciines are distributed into breast milk. Tetracyciines are distributed into milk following systemic admi istration. Because of the potential for serious adverse reaction in nursing infants, a decision should be made whether to discontinue nursing or discontinue the drug. taking into account the importance of the drug to the mother.Effects on Ability to Drive and use Machines
Oxytetracycline topical preparations are not expected to have an influence on the ability to drive or operate machinery. However, directly following the application of the ophthalmic dosage form, a short period of less acute vision may occur.Undesirable Effects
TERRAMYCIN is an antibiotic of low toxicity. Allergic reactions,
including contact dermatitis, due to individual hypersensitivity
have been reported. If such reactions occur, therapy should be
discontinued. Increased lacrimation, a transient stinging or burning sensation, and a foreign body sensation have been reported occasionally with ophthalmic tetracycline products.

Overdose :

No cases of overdosage with topical use of oxytetraycline have
been reported.

PHARMACOLOGICAL PROPERTIES :

Pharmacodynamic Properties
Oxytetracycline is a product of the metabolism of Strepotomyces
rimosus and is one of the family of tetracycline antibiotics.
Oxytetracycline is primarily bacteriostatic and is thought to exert
its antimicrobial effect by the inhibition of protein synthesis.
Oxytetracycline is active against a wide range of gram-negative
and gram-positive organisms. The drugs in the tetracycline class have similar antimicrobial spectra, and cross resistance among them is common. Polymyxin B Sulfate, one of a group of related antibiotics derived from Bacillus polymyxa, is bactericidal. This action is exclusively against gram-negaiive organisms. It is thought to act by altering the structure of the bacterial membrane resulting in leakage of essential intracellular components, it is particularly effective against Pseudomonas aeruginosa and Haemophitus aegytpius, frequently found in local infections of the eye. Thus the combination of TERRAMYCIN and POlymyxin B sulfate is a’ particularly effective antimicrobial combination against primarily causative or secondarily infected organisms. One mg of pure Polyrnxin B is equivalent to 10000 units.

Pharmacokinetic Properties :

Oxytetracycline:
In one study in rabbits with abraded corneas, oxytetracycline
hydrochloride concentrations of 28 mcg I ml were detected in the
aqueous humor 30 minutes after 5-minute bathing of the eye with
a solution containing 5 mg I ml oxytetracycline.Polymyxin B:
Polymyxin B is poorly absorbed from mucous membranes. In one study in rabbits, 0.1 mcg/ml concentrations of polymyxin B were detected in the aqueous humor and vitreous humor following six topical applications of 0.25% polymyxin B, one every 10 minutes ..